Articles & Interviews

The Neutrino 2018 conference is underway this week in Germany, where hundreds of physicists who study these elusive particles gather to discuss the latest developments in the field. Just what is it that these researchers do? Why are neutrinos such a big deal?

The answer is…The Standard Model.
The Standard Model is a mathematical theory proposed by Sheldon Glashow, Steven Weinberg and Abdus Salam in the latter half of the 20th century to describe fundamental particles and how they interact. It incorporated all that was known about subatomic world at the time and predicted the existence of additional particles as well.
After many years of experiments, and even with the birth of a new era of experiments with the construction of particle colliders like the Large Hadron Collider (LHC), the Standard Model has survived to most of the challenges. Its predictions were confirmed to an incredible precision, which makes the Standard Model one of the most succesfull scientific theories in the history of mankind.

The model which describes the world around us is called “The Standard Model” of particle physics. It includes many particles like the very well know electron, the photon, the Higgs particle (sometimes called The God Particle), the quarks and many more.

New observations of the ultra-diffuse galaxy NGC1052-DF2, published in Nature by van Dokkum et al., seem to show that it contains an unusually low amount of dark matter, perhaps barely any at all. This conclusion was reached after independently computing the luminous and gravitational mass of the galaxy, which, contrary to all other galaxies observed up to date, seem to match. This means that there is little room for the presence of non-luminous (or “dark”) matter in NGC1052-DF2. This striking observation may pose a challenge to popular dark matter paradigms and raises the question of what astrophysical processes could have lead to its formation.

The observed antineutrino ﬂux from nuclear reactors is consistently lower than predicted. This anomaly could hint at oscillations of active neutrinos into a new sterile neutrino species, or it could simply be a reﬂection of underestimated systematic uncertainties in the theoretical ﬂux prediction. We review the status of both hypothesis in view of recent developments. In particular, we scrutinize recent Daya Bay results, which aim to determine whether the deﬁcit depends on the isotope from which neutrinos are produced (as would be likely if the problem is with the ﬂux prediction), or is independent thereof (as would be expected if the sterile neutrino hypothesis is true). We also comment on new short-baseline data, and we discuss reactor data in the context of a global ﬁt.
Please see document attached.

A recent analysis done by A.Donini et. al [1] measures the density proﬁle of the Earth using atmospheric neutrinos.
Even though neutrinos are weakly interacting particles, cosmic rays scattering with the nuclei of the atmosphere produce a high energetic neutrino ﬂux with a non-negligible probability to interact with the nucleons of the Earth, when passing through it. Using a one-year muon data set measured by the IceCube neutrino telescope [2], it is possible to infer the Earth’s density proﬁle. This method provides a new way to study Earth’s internal structure and although the idea is not new, this work represents the ﬁrst attempt at applying it using actual data. This is the ﬁrst time we can actually see the interior of the Earth by means of neutrino tomography and obtain non-trivial results.

Rachel Houtz recently wrote an article for El País. She explains for the general public how a recent precision measurement of the fine-structure constant restricts dark photon parameters space. The article appeared on the El País website on April 18, 2018.

A recent announcement from the Experiment to Detect the Global Epoch of Reionization Signature (EDGES) [1], published in Nature on March 1st, 2018, has caught the attention of the cosmology and particle physics community worldwide. The EDGES collaboration has announced an observation based on a measurement of the 21-centimeter (21cm) hyperﬁne transition in neutral hydrogen that calls into question the legitimacy of the Lambda Cold Dark Matter model (ΛCDM), a theory that treats the entirety of dark matter as cold and non-interacting, and has been held in high regard for accurately modeling current cosmological observations over a huge range of scales.

One possible solution to the Dark Matter puzzle is the extension of the Standard Model of particle physics by sterile neutrinos, which, unlike the known neutrinos, do not interact via the fundamental forces of the Standard Model, they only interact gravitationally. Sterile neutrinos represent a natural extension to the Standard Model and feature in various neutrino mass generation mechanism

One of the most fascinating mysteries of physics today is the nature of dark matter. We know from many astrophysical and cosmological observations that a large fraction of matter in the universe is non-baryonic, invisible matter, called Dark Matter (DM). DM interacts gravitationally with ordinary matter and remains hidden to us because it doesn’t interact with the electromagnetic spectrum, and is therefore invisible to current instruments.

High-energy cosmic rays, i.e., particles traversing the space at energies which are much larger than their rest masses, provide a probe of galactic high-energy processes. They may shed light on the nature of such intriguing phenomenon as Dark Matter (DM) by maybe enabling observation of DM annihilation or decay.

Einstein’s theory of relativity interprets gravity as an eﬀect of the curvature of spacetime. As massive objects move, they should produce ripples in spacetime. These ripples would carry energy in the form of gravitational radiation, and thus they were dubbed “gravitational waves” (GWs).